The present invention relates to a hydraulic control device for rotating a cam shaft of an internal combustion engine.
More particularly it relates to a hydraulic control device which has a couple member which is longitudinally displaceable by pressure force and has a first toothing engaging a toothing at an inner circumference of a cam shaft and supported in a sprocket wheel driven by the internal combustion engine and a second toothing engaging with an inner toothing of a sprocket wheel bore, wherein the couple member is actually displaceable by a liquid pressure controlled by a magnet valve.
Hydraulic control devices of the above-mentioned general type are known in the art. One such hydraulic control device is disclosed in the German patent document DE-OS 32 47 916. In such a known control device in particular the pump and the magnet valve are arranged externally, which is relatively complicated particularly in view of the necessary pressure medium connections and also entails a considerable cost in construction.